Non-contact type power receiver and non-contact type battery

ABSTRACT

A non-contact type power receiver may includes: a plurality of power receiving coils receiving power in a non-contact manner; a plurality of rectifying units switching to rectify the power received from the plurality of power receiving coils; and a control unit controlling the switching by the plurality of rectifying units to control respective levels of the power rectified by the plurality of rectifying units.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to, and the benefit of Korean Patent Application No. 10-2014-0120455 filed on Sep. 11, 2014, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

This application relates to a non-contact type power receiver and a non-contact type battery capable of receiving power in a non-contact manner.

Electronic devices are operated using electricity as an energy source.

Electrical power as an energy source needs to be supplied to electronic devices in order for the electronic devices to operate. Electronic devices may generate power using a self-generation scheme, or may receive power supplied by external power sources.

In order for electronic devices to receive power supplied by external power sources, a power supply may be required to transfer power from power supply facilities to the electronic devices.

A contact-type power supply device, which is directly connected to an electronic device through a connector, or the like, is commonly used to supply power to a rechargeable battery provided in the electronic device. Alternatively, power may be supplied to a battery provided in an electronic device in a non-contact manner, as detailed in the following Related Art Document.

However, the following Related Art Document does not disclose techniques for obtaining balance between power levels in a plurality of battery cells of a battery and significantly increasing effective currents of the battery cells in a case in which power is applied to the battery in a non-contact manner.

RELATED ART DOCUMENT

(Patent Document 1) Korean Patent Laid-Open Publication No. 10-2013-0054897

SUMMARY

An exemplary embodiment in the present disclosure may provide a non-contact type power receiver and a non-contact type battery capable of controlling the charging of power with respect to each of a plurality of battery cells in a non-contact manner.

According to an exemplary embodiment in the present disclosure, a non-contact type power receiver may include: a plurality of power receiving coils receiving power in a non-contact manner; a plurality of rectifying units switching to rectify the power received from the plurality of power receiving coils; and a control unit controlling the switching by the plurality of rectifying units to control respective levels of the power rectified by the plurality of rectifying units.

According to another exemplary embodiment in the present disclosure, a non-contact type power receiver may include: a plurality of power receiving coils receiving power in a non-contact manner; a plurality of rectifying units switching to rectify the power received from the plurality of power receiving coils; and a control unit controlling the switching by the plurality of rectifying units, depending on coupling coefficients between each of the plurality of power receiving coils and a plurality of power transmitting coils which transmit the power to the plurality of power receiving coils, to control respective levels of the power rectified by the plurality of rectifying units.

According to another exemplary embodiment in the present disclosure, a non-contact type battery may include: a plurality of power receiving coils receiving power in a non-contact manner; a plurality of rectifying units switching to rectify the power received from the plurality of power receiving coils; a plurality of regulators regulating the power rectified by the plurality of rectifying units into charging power; a plurality of battery cells charged with the charging power from the plurality of regulators; and a control unit controlling the switching by the plurality of rectifying units to control respective levels of the power charged in the plurality of battery cells.

BRIEF DESCRIPTION OF DRAWINGS

The above and other aspects, features and advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIGS. 1A and 1B are views illustrating applications of a charger according to an exemplary embodiment in the present disclosure;

FIGS. 2A and 2B are circuit diagrams schematically illustrating examples of a charger and a battery according to exemplary embodiments in the present disclosure;

FIGS. 3A and 3B are circuit diagrams schematically illustrating examples of a power supply unit used in a charger according to exemplary embodiments in the present disclosure;

FIGS. 4A through 4D are circuit diagrams schematically illustrating first to fourth examples of a power charging unit according to exemplary embodiments in the present disclosure;

FIGS. 5A through 5C are views illustrating examples and applications of a battery according to exemplary embodiments in the present disclosure;

FIGS. 6A through 6D, FIGS. 7A through 7D, and FIGS. 8A and 8B are views illustrating examples of a power charging operation according to exemplary embodiments in the present disclosure;

FIGS. 9A and 9B are flowcharts illustrating examples of a method for sensing a coupling coefficient according to exemplary embodiments in the present disclosure;

FIGS. 10A and 10B are circuit diagrams schematically illustrating examples of data communications between a charger and a battery according to exemplary embodiments in the present disclosure;

FIG. 11 is a circuit diagram schematically illustrating an example of controlling power transmitted from a charger to a battery according to an exemplary embodiment in the present disclosure;

FIG. 12 is a circuit diagram schematically illustrating an example of controlling power transmitted from a charger to a plurality of batteries according to an exemplary embodiment in the present disclosure; and

FIGS. 13A through 13D are views illustrating an example of a switching control of an active rectifier in a battery according to an exemplary embodiment in the present disclosure.

DETAILED DESCRIPTION

Exemplary embodiments in the present disclosure will now be described in detail with reference to the accompanying drawings.

The disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

In the drawings, the shapes and dimensions of elements may be exaggerated for clarity, and the same reference numerals will be used throughout to designate the same or like elements.

FIGS. 1A and 1B are views illustrating applications of a charger according to an exemplary embodiment in the present disclosure.

Referring to FIGS. 1A and 1B, a charger A according to an exemplary embodiment in the present disclosure may transmit power to one or more electronic devices, such as a cellular phone, a tablet personal computer (PC), a laptop PC, or the like, having a battery B including a plurality of battery cells, in a non-contact manner. In addition, the charger A according to the exemplary embodiment may transmit power to a plurality of cellular phones, tablet PCs, laptop PCs, or the like, having batteries B1 and B2 in a non-contact manner. Here, the non-contact manner may refer to a manner in which a direct connection is not made between conductors on a transmitting side and a receiving side while power is being transmitted from the transmitting side to the receiving side, namely, a contactless scheme, a wireless transmitting scheme, or the like.

FIGS. 2A and 2B are circuit diagrams schematically illustrating examples of a charger and a battery according to exemplary embodiments in the present disclosure.

Referring to FIGS. 2A and 2B, the charger A according to exemplary embodiments in the present disclosure may include a power supply unit 110 transmitting power in a non-contact manner. The power supply unit 110 may include a power converting unit 111 providing preset power, and power transmitting coils CTx1, CTx11, CTx12, . . . , CTx21, and CTx22 transmitting the power from the power converting unit 111 in a non-contact manner.

The charger A may include a single power transmitting coil CTx1 as illustrated in FIG. 2A or may include a plurality of power transmitting coils CTx11, CTx12, . . . , CTx21, and CTx22 as illustrated in FIG. 2B in order to improve power transmission efficiency. The number of power transmitting coils CTx11, CTx12, . . . , CTx21, and CTx22 may correspond to the number of power receiving coils CRx11, CRx12, . . . , CRx21, and CRx22 disposed on a power receiving side.

Referring to FIGS. 2A and 2B, the battery B may include a power charging unit 120 and a battery unit 130. The power charging unit 120 may include a plurality of power charging units 121-1, 121-2, 122-1, and 122-2 corresponding to a plurality of battery cells BC11, BC12, BC21, and BC22 of the battery unit 130, respectively, and the plurality of power charging units 121-1, 121-2, 122-1, and 122-2 may include power receiving coils CRx11, CRx12, CRx21, and CRx22 and power charging control units L11, L12, L21, and L22, respectively, in order to charge corresponding battery cells BC11, BC12, BC21, and BC22 with power.

The power receiving coils CRx11, CRx12, CRx21, and CRx22 may receive the power from the power transmitting coils CTx1, CTx11, CTx12, . . . , CTx21, and CTx22 of the charger A in the non-contact manner, and the power charging control units L11, L12, L21, and L22 may charge the battery cells BC11, BC12, BC21, and BC22 with the power from the power receiving coils CRx11, CRx12, CRx21, and CRx22, and may control current values of the power charged in the corresponding battery cells BC11, BC12, BC21, and BC22. The power charged in the corresponding battery cells BC11, BC12, BC21, and BC22 may be controlled depending on coupling coefficients which are set between the power transmitting coils CTx1, CTx11, CTx12, . . . , CTx21, and CTx22 and the power receiving coils CRx11, CRx12, CRx21, and CRx22. The battery unit 130 may include at least one battery cell group, in which a plurality of battery cells are connected to each other in series.

The coupling coefficients between the power transmitting coils and the power receiving coils will be described in detail with reference to FIGS. 9A and 9B.

Meanwhile, in a case in which the charger A and the battery B described above are configured as a single charger, the charger may function as the power transmitting device A and the power receiving device B.

FIGS. 3A and 3B are circuit diagrams schematically illustrating examples of a power supply unit used in a charger according to exemplary embodiments in the present disclosure.

The power supply unit 110 may include the power converting unit 111 switching the power and a power transmitting coil CTx1. The power supply unit 110 may include a plurality of power transmitting coils.

The power converting unit 111 may include a switching unit 111 b, a switching control unit 111 a, and a communications unit 111 c. The switching unit 111 b may be electrically connected to the power transmitting coil CTx1, switch input power, and wirelessly transmit the power through the power transmitting coil CTx1. The switching control unit 111 a may provide switching control signals SQ1 and SQ2, or SQ1 to SQ4, for controlling the switching operation of the switching unit 111 b. In a case in which the power transmitting coil is provided in plural, a plurality of switching units may be connected to the plurality of power transmitting coils, respectively, or the plurality of power transmitting coils may be connected to at least one switching unit.

The communications unit 111 c may receive charging state information from a wireless power charging target device and provide the charging state information to the switching control unit 111 a so that the switching control unit 111 a may control a switching duty, switching on/off times, and the like, thereby performing a rapid power charging function, a function of maintaining a power balance between battery cells, or the like.

The switching unit 111 b may include at least two switches Q1 and Q2 as illustrated in FIG. 3A. For example, the switches Q1 and Q2 may be field effect transistors (FETs), but are not limited thereto. The switches Q1, Q2, Q3 and Q4 may have a half bridge structure or a full bridge structure as illustrated in FIG. 3B. However, the switches Q1, Q2, Q3 and Q4 are not limited thereto, and the configuration thereof may be variously modified. Driving power Vcc may be supplied to the switches Q1 and Q2. A voltage level of the supplied driving power Vcc may be fixed or varied.

FIGS. 4A through 4D are circuit diagrams schematically illustrating first to fourth examples of a power charging unit according to exemplary embodiments in the present disclosure.

Referring to FIGS. 4A through 4D, the power charging unit according to exemplary embodiments in the present disclosure may include a power receiving coil CRx and a power charging control unit L.

The power receiving coil CRx may wirelessly receive power from a corresponding power transmitting coil CTx of the power supply unit. The power charging control unit L may control the wirelessly received power and charge a corresponding battery cell BC with the power.

The power charging control unit L may include a rectifying unit La, a regulator Lb, and a control unit Lc.

The rectifying unit La may rectify the power received from the power receiving coil CRx, and the regulator Lb may convert the rectified power into power appropriate for charging to control the power charging of the corresponding battery cell BC. The control unit Lc may detect a state of the power transmitted to the power receiving coil CRx and wirelessly transmit power state information to the power supply unit.

To this end, the control unit Lc may detect the state of the power from the power receiving coil CRx or the power provided from the regulator Lb to the battery cell BC.

Meanwhile, the control unit Lc may wirelessly transmit the power state information having a pulse form to a power transmitting side through the power receiving coil CRx, and may include a separate communications unit Com to transmit the power state information detected by a detecting unit Det to the power transmitting side through the communications unit Com in a preset communications scheme.

FIGS. 5A through 5C are views illustrating examples and applications of a battery according to exemplary embodiments in the present disclosure.

Referring to FIG. 5A, the battery B according to an exemplary embodiment in the present disclosure may include, for example, six battery cells BC11 to BC23. The six battery cells BC11 to BC23 may include three battery cells BC11, BC12, and BC13 and three battery cells BC21, BC22, and BC23, connected to each other in series, respectively, each of which forms a single battery cell group. Two battery cell groups BC11, BC12, and BC13 and BC21, BC22, and BC23 may be configured to be connected to each other in parallel. The battery B according to the exemplary embodiment in the present disclosure may be used in a cellular phone, a tablet PC, a laptop PC, or the like, but details thereof will be omitted.

In addition, as illustrated in FIG. 5A, six power receiving coils CRx11 to CRx23 corresponding to the six battery cells BC11 to BC23 may be provided in the battery B, and may wirelessly receive the power from one or more power transmitting coils of the charger A.

For example, the charger A may include a single power transmitting coil CTx1, as illustrated in FIG. 5A, or may include a plurality of power transmitting coils as illustrated in FIG. 5B. For example, six power transmitting coils CTx11 to CTx23 corresponding to the six power receiving coils CRx11 to CRx23 may be provided as illustrated in FIG. 5B, but the number of power transmitting coils is not limited thereto.

In addition, referring to FIG. 5C, the charger A may include a plurality of power transmitting coils C_(Tx1) and C_(Tx2), and the battery B may also include a plurality of power receiving coils CRx11 and CRx21, for example, six or more power receiving coils or less than six power receiving coils.

FIGS. 6A through 6D, FIGS. 7A through 7D, and FIGS. 8A and 8B are views illustrating examples of a power charging operation according to exemplary embodiments in the present disclosure.

Referring to FIGS. 6A through 6D, levels of voltages V_(Rx1), V_(Rx2), and V_(Rx3) of power transferred to the power receiving coils may be different from each other. Therefore, the power supply unit may differently set the voltages V_(Rx1), V_(Rx2), and V_(Rx3) of the power transmitted by the power transmitting coils to the corresponding power receiving coils in a balanced state depending on the power state information.

As illustrated in FIG. 6A, the power supply unit may maintain a balance in power levels by controlling the amounts of power received by the plurality of power receiving coils to be constant, on the basis of a maximum voltage V_(Rx2) among the voltages V_(Rx1), V_(Rx2), and V_(Rx3) received by the plurality of power receiving coils depending on the power state information from the power charging unit. On the contrary, as illustrated in FIG. 6D, the power supply unit may maintain a balance in power levels by controlling the amounts of power received by the plurality of power receiving coils to be constant on the basis of a minimum voltage V_(Rx2) among the voltages V_(Rx1), V_(Rx2), and V_(Rx3) received by the plurality of power receiving coils.

In order to control the amounts of power transmitted by the power transmitting coils, switching on duties or switching off duties of the corresponding switch circuits may be controlled, as illustrated in FIG. 6B, or switching dead times of the corresponding switch circuits may be controlled, as illustrated in FIG. 6C.

The above-mentioned charging operations will be described in more detail with reference to FIGS. 7A through 7D.

Referring to FIG. 7A, for example, the charger according to an exemplary embodiment in the present disclosure may include a single power transmitting unit Tx1 and the power transmitting unit Tx1 may wirelessly transmit power to at least two power receiving units Rx1 and Rx2.

Here, the power transmitting unit Tx1 may have the configuration illustrated in FIG. 3A or 3B, and each of the power receiving units Rx1 and Rx2 may have the configuration illustrated in any one of FIGS. 4A through 4D.

For example, in a case in which a voltage V_(Rx2) (or a current I_(Rx2)) detected by a second power receiving unit Rx2 is lower than a voltage V_(Rx1) (or a current I_(Rx1)) detected by a first power receiving unit Rx1, that is, in a case of {circle around (1)} in FIG. 7A, the level of the power wirelessly transmitted by the power transmitting unit Tx1 may be increased so that the voltage V_(Rx2) detected by the second power receiving unit Rx2 reaches a reference voltage V_(Ref). Therefore, the voltage V_(Rx1) detected by the first power receiving unit Rx1 receiving the power wirelessly transmitted by the power transmitting unit Tx1 may exceed the reference voltage V_(Ref); however, rapid power charging may be achieved. Here, the reference voltage V_(Ref) may be set to allow a maximum current to flow in a corresponding battery cell.

In a case of {circle around (2)} in FIG. 7A, the level of the power wirelessly transmitted by the power transmitting unit Tx1 may be increased so that the voltage V_(Rx1) detected by the first power receiving unit Rx1 reaches the reference voltage V_(Ref). Therefore, the voltage V_(Rx2) detected by the second power receiving unit Rx2 receiving the power wirelessly transmitted by the power transmitting unit Tx1 may not reach the reference voltage V_(Ref); however, power transmission efficiency may be increased.

Referring to FIG. 7B, for example, the charger according to an exemplary embodiment in the present disclosure may include a single power transmitting unit Tx1 and the power transmitting unit Tx1 may wirelessly transmit power to at least three power receiving units Rx1, Rx2, and Rx3.

For example, in a case in which a voltage V_(Rx2) (or a current I_(Rx2)) detected by a second power receiving unit Rx2 is higher than a voltage V_(Rx1) (or a current I_(Rx1)) detected by a first power receiving unit Rx1 and a voltage V_(Rx3) (or a current I_(Rx3)) detected by a third power receiving unit Rx3 is lower than the voltage V_(Rx1) (or the current I_(Rx1)) detected by the first power receiving unit Rx1, that is, in a case of {circle around (1)} in FIG. 7B, the level of the power wirelessly transmitted by the power transmitting unit Tx1 may be increased so that the lowest voltage V_(Rx3) detected by the third power receiving unit Rx3 reaches a reference voltage V_(Ref). Therefore, the voltage V_(Rx1) detected by the first power receiving unit Rx1 receiving the power wirelessly transmitted by the power transmitting unit Tx1 and the voltage V_(Rx2) detected by the second power receiving unit Rx2 receiving the power wirelessly transmitted by the power transmitting unit Tx1 may exceed the reference voltage V_(Ref), and in this case, rapid power charging may be achieved, while power transmission efficiency may be decreased.

In a case of {circle around (2)} in FIG. 7B, the level of the power wirelessly transmitted by the power transmitting unit Tx1 may be increased so that the intermediate voltage V_(Rx1) detected by the first power receiving unit Rx1 reaches the reference voltage V_(Ref). Therefore, the voltage V_(Rx2) detected by the second power receiving unit Rx2 receiving the power wirelessly transmitted by the power transmitting unit Tx1 may exceed the reference voltage V_(Ref), and the voltage V_(Rx3) detected by the third power receiving unit Rx3 receiving the power wirelessly transmitted by the power transmitting unit Tx1 may not reach the reference voltage V_(Ref).

In a case of {circle around (3)} in FIG. 7B, the level of the power wirelessly transmitted by the power transmitting unit Tx1 may be increased so that the highest voltage V_(Rx2) detected by the second power receiving unit Rx2 reaches the reference voltage V_(Ref). Therefore, the voltage V_(Rx1) detected by the first power receiving unit Rx1 receiving the power wirelessly transmitted by the power transmitting unit Tx1 and the voltage V_(Rx3) detected by the third power receiving unit Rx3 receiving the power wirelessly transmitted by the power transmitting unit Tx1 may not reach the reference voltage V_(Ref), and in this case, power transmission efficiency may be increased, while a voltage charging speed may be decreased.

Referring to FIG. 7C, for example, the charger according to an exemplary embodiment in the present disclosure may include at least two power transmitting units Tx1 and Tx2 and the power transmitting units Tx1 and Tx2 may wirelessly transmit power to at least two power receiving units Rx1 and Rx2.

For example, in a case in which a voltage V_(Rx2) (or a current I_(Rx2)) detected by a second power receiving unit Rx2 is lower than a voltage V_(Rx1) (or a current I_(Rx1)) detected by a first power receiving unit Rx1, that is, in a case of {circle around (1)} in FIG. 7C, the levels of the power wirelessly transmitted by first and second power transmitting units Tx1 and Tx2 may be controlled so that the voltage V_(Rx1) detected by the first power receiving unit Rx1 becomes the same as the voltage V_(Rx2) detected by the second power receiving unit Rx2. Then, the levels of the power wirelessly transmitted by the first and second power transmitting units Tx1 and Tx2 may be controlled so that the voltage V_(Rx1) detected by the first power receiving unit Rx1 and the voltage V_(Rx2) detected by the second power receiving unit Rx2 are changed to be equal to the reference voltage V_(Ref).

In a case of {circle around (2)} in FIG. 7C, the levels of the power wirelessly transmitted by the first and second power transmitting units Tx1 and Tx2 may be controlled so that the voltage V_(Rx2) detected by the second power receiving unit Rx2 becomes the same as the voltage V_(Rx1) detected by the first power receiving unit Rx1. Then, the levels of the power wirelessly transmitted by the first and second power transmitting units Tx1 and Tx2 may be controlled so that the voltage V_(Rx1) detected by the first power receiving unit Rx1 and the voltage V_(Rx2) detected by the second power receiving unit Rx2 are changed to be equal to the reference voltage V_(Ref).

On the other hand, in a case of {circle around (3)} or {circle around (4)} in FIG. 7C, the levels of the power wirelessly transmitted by the first and second power transmitting units Tx1 and Tx2 may be increased so that the voltage V_(Rx2) detected by the second power receiving unit Rx2 reaches the reference voltage V_(Ref), or so that the voltage V_(Rx1) detected by the first power receiving unit Rx1 reaches the reference voltage V_(Ref). Such an increase in levels of power may be controlled depending on a degree of coupling between the power transmitting unit and the power receiving unit, thereby maintaining a balance between the battery cells and/or rapidly charging the battery cells with the maximum allowable current.

Referring to FIG. 7D, for example, the charger according to an exemplary embodiment in the present disclosure may include at least two power transmitting units Tx1 and Tx2 and the power transmitting units Tx1 and Tx2 may wirelessly transmit power to at least three power receiving units Rx1, Rx2, and Rx3.

In a case in which a voltage V_(Rx2) (or a current I_(Rx2)) detected by a second power receiving unit Rx2 is higher than a voltage V_(Rx1) (or a current I_(Rx1)) detected by a first power receiving unit Rx1 and a voltage V_(Rx3) (or a current I_(Rx3)) detected by a third power receiving unit Rx3 is lower than the voltage V_(Rx1) (or the current I_(Rx1)) detected by the first power receiving unit Rx1, that is, in a case of {circle around (1)} in FIG. 7D, the levels of the power wirelessly transmitted by first and second power transmitting units Tx1 and Tx2 may be controlled so that the voltage V_(Rx1) detected by the first power receiving unit Rx1 and the voltage V_(Rx2) detected by the second power receiving unit Rx2 become the same as the lowest voltage V_(Rx3) detected by the third power receiving unit Rx3. Then, the levels of the power wirelessly transmitted by the first and second power transmitting units Tx1 and Tx2 may be controlled so that the voltage V_(Rx1) detected by the first power receiving unit Rx1, the voltage V_(Rx2) detected by the second power receiving unit Rx2, and the voltage V_(Rx3) detected by the third power receiving unit Rx3 are changed to be equal to a reference voltage V_(Ref).

In a case of {circle around (2)} in FIG. 7D, the levels of the power wirelessly transmitted by the first and second power transmitting units Tx1 and Tx2 may be controlled so that the voltage V_(Rx1) detected by the first power receiving unit Rx1 and the voltage V_(Rx3) detected by the third power receiving unit Rx3 become the same as the highest voltage V_(Rx2) detected by the second power receiving unit Rx2. Then, the levels of the power wirelessly transmitted by the first and second power transmitting units Tx1 and Tx2 may be controlled so that the voltage V_(Rx1) detected by the first power receiving unit Rx1, the voltage V_(Rx2) detected by the second power receiving unit Rx2, and the voltage V_(Rx3) detected by the third power receiving unit Rx3 are changed to be equal to the reference voltage V_(Ref).

In a case of {circle around (3)} in FIG. 7D, the levels of the power wirelessly transmitted by the first and second power transmitting units Tx1 and Tx2 may be controlled so that the voltage V_(Rx2) detected by the second power receiving unit Rx2 and the voltage V_(Rx3) detected by the third power receiving unit Rx3 become the same as the intermediate voltage V_(Rx1) detected by the first power receiving unit Rx1. Then, the levels of the power wirelessly transmitted by the first and second power transmitting units Tx1 and Tx2 may be controlled so that the voltage V_(Rx1) detected by the first power receiving unit Rx1, the voltage V_(Rx2) detected by the second power receiving unit Rx2, and the voltage V_(Rx3) detected by the third power receiving unit Rx3 are changed to be equal to the reference voltage V_(Ref).

In addition, in a case of {circle around (4)}, {circle around (5)} or {circle around (6)} in FIG. 7D, the levels of the power wirelessly transmitted by the first and second power transmitting units Tx1 and Tx2 may be increased so that the voltage V_(Rx2) detected by the second power receiving unit Rx2 reaches the reference voltage V_(Ref), or the levels of the power wirelessly transmitted by the first and second power transmitting units Tx1 and Tx2 may be increased so that the voltage V_(Rx3) detected by the third power receiving unit Rx3 reaches the reference voltage V_(Ref), or the levels of the power wirelessly transmitted by the first and second power transmitting units Tx1 and Tx2 may be increased so that the voltage V_(Rx1) detected by the first power receiving unit Rx1 reaches the reference voltage V_(Ref). The levels of the power wirelessly transmitted by the first and second power transmitting units Tx1 and Tx2 may be increased so that the voltages detected by the power receiving units coupled to the first and second power transmitting units Tx1 and Tx2 reach the reference voltage V_(Ref). However, in this case, the power may also be wirelessly transmitted to the power receiving unit disposed in the vicinity of the power receiving units coupled to the first and second power transmitting units Tx1 and Tx2.

Meanwhile, referring to FIGS. 8A and 8B, in a case in which the charger according to an exemplary embodiment in the present disclosure includes at least two power transmitting units Tx1 and Tx2 as illustrated in FIGS. 7C and 7D, a wireless coupling relationship may be set between the power transmitting units Tx1 and Tx2 and two or more power receiving units Rx1, Rx2, and Rx3. For example, a power receiving unit receiving the highest amount of power from a corresponding power transmitting unit transmitting power wirelessly has the highest wireless power coupling relationship.

To this end, a power coupling relationship between corresponding power transmitting units and power receiving units may be set depending on power state information including information on voltages or currents detected by the power receiving units Rx1, Rx2, and Rx3. For example, two power transmitting units Tx1 and Tx2 may be sequentially turned on/off to search for the power receiving unit receiving the highest amount of power from the corresponding power transmitting units, as illustrated in FIG. 8A, or amounts of power wirelessly transmitted by the power transmitting units Tx1 and Tx2 may be alternately varied to search for the power receiving unit having the highest amount of change in levels of the power received from the corresponding power transmitting units, as illustrated in FIG. 8B.

FIGS. 9A and 9B are flowcharts illustrating examples of a method for sensing a coupling coefficient according to exemplary embodiments in the present disclosure.

First, referring to FIG. 9A, in a sensing time in which a coupling coefficient is sensed according to a preset period (S11), a voltage or current level of power transmitted by a power transmitting coil of a power transmitting unit and a voltage or current level of power applied to a power receiving coil or a battery cell of a power receiving unit may be detected (S21), and a coupling coefficient between a power transmitting side and a power receiving side may be calculated (S31).

The calculated coupling coefficient may be transferred to a control circuit controlling power transmitted by the power transmitting unit (S41).

Referring to FIG. 9B, in a case in which a charging state is varied (S12), a voltage or current level of power transmitted by a power transmitting coil of a power transmitting unit and a voltage or current level of power applied to a power receiving coil or a battery cell of a power receiving unit may be detected (S22), and a coupling coefficient between a power transmitting side and a power receiving side may be calculated (S32). The calculated coupling coefficient may be transferred to a control circuit controlling power transmitted by the power transmitting unit (S42).

Here, the charging state may be varied by new power charging conditions, such as changes in the position of the charger or the battery or the introduction of an additional battery in addition to the battery charged with power from the charger. An example of a method for detecting the above-mentioned power charging conditions may include detecting a case in which the voltage or current level of the power applied to the power receiving coil or the battery cell of the power receiving unit is changed to be equal to a reference level or higher.

The coupling coefficient between the charger and the battery described above may be calculated by sequentially turning on/off the power transmitting units Tx1 and Tx2 to search for the power receiving units receiving the highest amount of power from the corresponding power transmitting units, as illustrated in FIG. 8A, or alternately varying the amounts of power wirelessly transmitted by the power transmitting units Tx1 and Tx2 to search for the power receiving unit having the highest amount of change in levels of power received from the corresponding power transmitting units, as illustrated in FIG. 8B.

First, a relationship between the voltage levels of the power applied to the power receiving coils or the battery cells of the power receiving units of the battery and the voltage levels of the power transmitted by the power transmitting coils of the power transmitting units of the charger may be represented by the following Equation 1:

$\begin{matrix} {\begin{bmatrix} V_{R \times 1} \\ V_{R \times 2} \end{bmatrix} = {\begin{bmatrix} C_{11} & C_{12} \\ C_{21} & C_{22} \end{bmatrix}\begin{bmatrix} V_{T \times 1} \\ V_{T \times 2} \end{bmatrix}}} & {{Equation}\mspace{14mu} 1} \end{matrix}$

Here, V_(Rx1) and V_(Rx2) indicate voltage levels of power applied to the power receiving coils or the battery cells of the power receiving units Rx1 and Rx2, respectively, V_(Tx1) and V_(Tx2) indicate voltage levels of power applied to the power transmitting coils of the power transmitting units Tx1 and Tx2, respectively, and C₁₁, C₁₂, C₂₁, and C₂₂ indicate coupling coefficients between the charger and the battery, that is, between the power receiving units Rx1 and Rx2 and the power transmitting units Tx1 and Tx2.

Here, two power transmitting coils and two power receiving coils are used by way of example, but the number of coils is not limited thereto. Meanwhile, even in a case in which the number of power transmitting coils and power receiving coils is three or more, a relationship between the voltage levels of the power applied to the power receiving coils or the battery cells of the power receiving units of the battery and the voltage levels of the power transmitted by the power transmitting coils of the power transmitting units of the charger may be represented in the same manner. In addition, C_(ij) indicates a coupling coefficient between V_(Rxi) and V_(Txj).

In a case in which the coupling coefficients are calculated by sequentially turning on/off the power transmitting units Tx1 and Tx2 to search for the power receiving unit receiving the highest amount of power from the corresponding power transmitting units, as illustrated in FIG. 8A, for example, when the power applied to the power transmitting unit Tx2 is turned off, the following Equation 2 may be obtained:

$\begin{matrix} {\begin{bmatrix} V_{R \times 1} \\ V_{R \times 2} \end{bmatrix} = {{\begin{bmatrix} C_{11} & C_{12} \\ C_{21} & C_{22} \end{bmatrix}\begin{bmatrix} V_{T \times 1} \\ 0 \end{bmatrix}} = \begin{bmatrix} {C_{11} \cdot V_{T \times 1}} \\ {C_{21} \cdot V_{T \times 1}} \end{bmatrix}}} & {{Equation}\mspace{14mu} 2} \end{matrix}$

Referring to Equation 2, the coupling coefficients C₁₁ and C₂₁ may be calculated by the following Equation 3:

$\begin{matrix} {\begin{bmatrix} C_{11} \\ C_{21} \end{bmatrix} = \begin{bmatrix} \frac{V_{R \times 1}}{V_{T \times 1}} \\ \frac{V_{R \times 2}}{V_{T \times 1}} \end{bmatrix}} & {{Equation}\mspace{14mu} 3} \end{matrix}$

Next, when the power applied to the power transmitting unit Tx1 is turned off, the coupling coefficients C₁₂ and C₂₂ may be calculated by the following Equation 4:

$\begin{matrix} {\begin{bmatrix} C_{12} \\ C_{22} \end{bmatrix} = \begin{bmatrix} \frac{V_{R \times 1}}{V_{T \times 2}} \\ \frac{V_{R \times 2}}{V_{T \times 2}} \end{bmatrix}} & {{Equation}\mspace{14mu} 4} \end{matrix}$

Meanwhile, in a case in which the coupling coefficients are calculated by alternately varying the amount of power wirelessly transmitted by the power transmitting units Tx1 and Tx2 to search for the power receiving unit having the highest amount of change in levels of power received from the corresponding power transmitting units, as illustrated in FIG. 8B, a relationship between changes in the voltage levels of the power applied to the power receiving coils or the battery cells of the power receiving units of the battery and changes in the voltage levels of the powers transmitted by the power transmitting coils of the power transmitting units of the charger may be represented by the following Equation 5:

$\begin{matrix} {\begin{bmatrix} {\Delta\; V_{R \times 1}} \\ {\Delta\; V_{R \times 2}} \end{bmatrix} = {\begin{bmatrix} C_{11} & C_{12} \\ C_{21} & C_{22} \end{bmatrix}\begin{bmatrix} {\Delta\; V_{T \times 1}} \\ {\Delta\; V_{T \times 2}} \end{bmatrix}}} & {{Equation}\mspace{14mu} 5} \end{matrix}$

Here, ΔV_(Rx1) and ΔV_(Rx2) indicate changes in voltage levels of power applied to the power receiving coils or the battery cells of the power receiving units Rx1 and Rx2, respectively, ΔV_(Tx1) and ΔV_(Tx2) indicate changes in voltage levels of power applied to the power transmitting coils of the power transmitting units Tx1 and Tx2, respectively, and C₁₁, C₁₂, C₂₁, and C₂₂ indicate be coupling coefficients between the charger and the battery, that is, between the power receiving units Rx1 and Rx2 and the power transmitting units Tx1 and Tx2.

First, when an output voltage of the power transmitting unit Tx2 is fixed (ΔV_(Tx2)=0) and an output voltage of the power transmitting unit Tx1 is varied by a predetermined level, voltage levels of power transmitted to the power receiving units Rx1 and Rx2 may be varied depending on a degree of coupling between the power receiving units Rx1 and Rx2 and the power transmitting unit Tx1, and this relationship may be represented by the following Equation 6:

$\begin{matrix} {\begin{bmatrix} {\Delta\; V_{R \times 1}} \\ {\Delta\; V_{R \times 2}} \end{bmatrix} = {{\begin{bmatrix} C_{11} & C_{12} \\ C_{21} & C_{22} \end{bmatrix}\begin{bmatrix} {\Delta\; V_{T \times 1}} \\ 0 \end{bmatrix}} = \begin{bmatrix} {{C_{11} \cdot \Delta}\; V_{T \times 1}} \\ {{C_{21} \cdot \Delta}\; V_{T \times 1}} \end{bmatrix}}} & {{Equation}\mspace{14mu} 6} \end{matrix}$

Referring to Equation 6, coupling coefficients C₁₁ and C₂₁ may be calculated by the following Equation 7:

$\begin{matrix} {\begin{bmatrix} C_{11} \\ C_{21} \end{bmatrix} = \begin{bmatrix} \frac{\Delta\; V_{R \times 1}}{\Delta\; V_{T \times 1}} \\ \frac{\Delta\; V_{R \times 2}}{\Delta\; V_{T \times 1}} \end{bmatrix}} & {{Equation}\mspace{14mu} 7} \end{matrix}$

Next, when an output voltage of the power transmitting unit Tx1 is fixed (ΔV_(Tx1)=0) and an output voltage of the power transmitting unit Tx2 is varied by a predetermined level, coupling coefficients C₁₂ and C₂₂ may be calculated by the following Equation 8:

$\begin{matrix} {\begin{bmatrix} C_{12} \\ C_{22} \end{bmatrix} = \begin{bmatrix} \frac{\Delta\; V_{R \times 1}}{\Delta\; V_{T \times 2}} \\ \frac{\Delta\; V_{R \times 2}}{\Delta\; V_{T \times 2}} \end{bmatrix}} & {{Equation}\mspace{14mu} 8} \end{matrix}$

Although the coupling coefficients are calculated on the basis of the voltage levels of the power applied to the power receiving coils or the battery cells and the voltage levels of the power applied to the power transmitting coils by way of example, they may be calculated by using current levels of power applied to the power receiving coils or the battery cells and current levels of power applied to the power transmitting coils.

FIGS. 10A and 10B are circuit diagrams schematically illustrating data communications between a charger and a battery according to exemplary embodiments in the present disclosure.

Referring to FIG. 10A, the power transmitting units Tx1 and Tx2 of the charger A may include power transmitting coils C_(Tx1) and C_(Tx2) and switching units 111 b 1 and 111 b 2. The switching units 111 b 1 and 111 b 2 may transfer power to the power transmitting coils C_(Tx1) and C_(Tx2), respectively, in order to calculate the coupling coefficients between the power transmitting side and the power receiving side as described above.

The switches Q11, Q21, Q12, and Q22 of the switching units 111 b 1 and 111 b 2 may switch driving power V_(DC1) and V_(DC2) depending on the switching control signals SQ11, SQ21, SQ12, and SQ22 from the switching control unit 111 a to transmit the power to the power receiving side through the corresponding power transmitting coils C_(Tx1) and C_(Tx2) in a non-contact manner.

The switching control unit 111 a may control power switching of the switching units 111 b 1 and 111 b 2 depending on information of the battery B transferred by the communications unit 111 c. For example, the switching control unit 111 a may control respective switching duties or on-off dead times of the switches Q11, Q21, Q12, and Q22 to adjust voltage levels V_(Tx1) and V_(Tx2) of the power output through the power transmitting coils C_(Tx1) and C_(Tx2), or may control voltage levels of the driving power V_(DC1) and V_(DC2) to adjust the voltage levels V_(Tx1) and V_(Tx2) of the power output through the power transmitting coils C_(Tx1) and C_(Tx2), or may control switching frequencies to adjust frequencies f_(Tx1) and f_(Tx2) at which the power is transmitted through the power transmitting coils C_(Tx1) and C_(Tx2).

The above-mentioned adjusting or controlling operations may be performed on the basis of the coupling coefficients between the power transmitting side and the power receiving side. Since information on the position, charging state, operating state, charging power, and the like, of the battery B is continuously needed for power charging of the charger A, the information may be transferred by bidirectional communications between the communications unit 111 c of the charger A and the communications unit Com of the battery B. In addition, information on the positions, power transmitting states, power switching operations, charging power, and the like, of the power transmitting coils C_(Tx1) and C_(Tx2) of the charger A may be transferred to the battery B through the communications unit Com of the battery B. In addition, the voltage or current levels of the power received by the power receiving coils C_(Rx1), C_(Rx2), C_(Rx3), C_(Rx4), C_(Rx5), and C_(Rx6) or of the power applied to the battery cells may be transferred to the charger A through the communications unit 111 c, and the voltage or current levels of the power applied to the power transmitting coils C_(Tx1) and C_(Tx2) may be transferred to the battery B through the communications unit Com. In addition, in a case in which the coupling coefficients between the power transmitting coils C_(Tx1) and C_(Tx2) of the charger A and the power receiving coils C_(Rx1), C_(Rx2), C_(Rx3), C_(Rx4), C_(Rx5), and C_(Rx6) of the battery B are calculated in the battery B, the calculated coupling coefficients may be transferred to the charger A through the communications unit.

The above-mentioned bidirectional communications may be performed by using various communications schemes such as Bluetooth, Zigbee®, Wi-Fi, near field communications (NFC), and the like, and various communication frequencies may be used.

Referring to FIG. 10B, the power may be transmitted and the information may be transferred between the power transmitting coil CTx of the charger A and the power receiving coil CRx of the battery B in the non-contact manner.

The power supply unit 110 of the charger A may include a power unit 111 e, a switching unit 111 b, a detecting unit 111 d and a control unit 111 a. The power unit 111 e may convert alternating current (AC) power into direct current (DC) power. The switching unit 111 b may switch the DC power from the power unit 111 e depending on a control of the control unit 111 a to transmit the DC power through the power transmitting coil CTx. The detecting unit 111 d may detect a power state of the power transmitting coil CTx. The control unit 111 a may control the switching of the switching unit 111 b depending on information detected by the detecting unit 111 d.

The battery B may include a rectifying unit La, a regulator Lb, and a control unit Lc. The rectifying unit La may rectify power from the power receiving coil CRx. The regulator Lb may regulate the rectified power to charging power which is appropriate for charging a battery cell Bc. The control unit Lc may control the operation of the regulator Lb.

The power transmitted to the power receiving coil CRx may be varied according to the operation of the regulator Lb, a power level change of the power receiving coil CRx may affect the power transmitting coil CTx by magnetic coupling between the power receiving coil CRx and the power transmitting coil CTx, the detecting unit 111 d may detect the power level change of the power receiving coil CRx and transfer the detected information to the control unit 111 a, and the control unit 111 a may control the switching operation of the switching unit 111 b depending on the detected information.

Communications may be performed between the battery B and the charger A, depending on the above-mentioned power level change. In addition, information on the voltage or current levels of the power received by the power receiving coils of the battery B, information on the voltage or current levels of the power applied to the battery cells of the battery B, the information on the position, the charging state, the operating state, and the charging power of the battery B, information on the voltage or current levels of the power applied to the power transmitting coils of the charger A, and information on the positions, the power transmitting states, the power switching operations, the charging power, and the like, of the power transmitting coils of the charger A may be transmitted and received using the communications in this scheme.

Here, in a case in which a plurality of power transmitting coils and power receiving coils are used, the information may be transmitted and received in a time division scheme.

The coupling coefficients between the power transmitting coils of the charger A and the power receiving coils of the battery B may be calculated on the basis of the transmitted and received information. In other words, the charger A may calculate the coupling coefficients on the basis of the transmitted and received information, or the battery B may calculate the coupling coefficients on the basis of the transmitted and received information and then transmit the calculated coupling coefficients to the charger A by the communications between the battery B and the charger A depending on the above-mentioned power level change.

The switching operation of the switching unit 111 b of the charger A may be controlled on the basis of the coupling coefficients between the power transmitting coils of the charger A and the power receiving coils of the battery B.

FIG. 11 is a circuit diagram schematically illustrating an example of controlling power transmitted from a charger to a battery according to an exemplary embodiment in the present disclosure.

Referring to FIG. 11, the power transmitting units Tx1 and Tx2 of the charger A may include the power transmitting coils C_(Tx1) and C_(Tx2) and the switching units 111 b 1 and 111 b 2. The switching units 111 b 1 and 111 b 2 may transfer power to the power transmitting coils C_(Tx1) and C_(Tx2), respectively, in order to calculate coupling coefficients between the power transmitting side and the power receiving side as described above.

The switches Q11, Q21, Q12, and Q22 of the switching units 111 b 1 and 111 b 2 may switch driving power V_(DC1) and V_(DC2) depending on switching control signals SQ11, SQ21, SQ12, and SQ22 from the switching control unit 111 a to transmit the power to the power receiving side through the corresponding power transmitting coils C_(Tx1) and C_(Tx2) in a non-contact manner.

The switching control unit 111 a may control power switching of the switching units 111 b 1 and 111 b 2 depending on information of the battery B transferred by the communications unit 111 c. For example, the switching control unit 111 a may control respective switching duties or on-off dead times of the switches Q11, Q21, Q12, and Q22 to adjust voltage levels V_(Tx1) and V_(Tx2) of the power output through the power transmitting coils C_(Tx1) and C_(Tx2), or may control voltage levels of the driving power V_(DC1) and V_(DC2) to adjust the voltage levels V_(Tx1) and V_(Tx2) of the power output through the power transmitting coils C_(Tx1) and C_(Tx2), or may control switching frequencies to adjust frequencies f_(Tx1) and f_(Tx2) at which the power is transmitted by the power transmitting coils C_(Tx1) and C_(Tx2).

The above-mentioned adjusting or controlling operation may be performed on the basis of the coupling coefficients between the power transmitting side and the power receiving side.

As an example, in a case in which a coupling coefficient between the first power transmitting coil C_(Tx1) and the first power receiving coil C_(Rx1) is low, the first power transmitting unit Tx1 may control respective switching frequencies of the switches Q11 and Q21 of the switching unit 111 b 1 to control the frequency f_(Tx1) at which the power is transmitted by the power transmitting coil C_(Tx1), in order to effectively control the power transferred to the first power receiving coil C_(Rx1).

As another example, in a case in which a coupling coefficient between the second power transmitting coil C_(Tx2) and the second power receiving coil C_(Rx2) is high, the second power transmitting unit Tx2 may control respective switching duties or on-off dead times of the switches Q12 and Q22 of the switching unit 111 b 2 to adjust the voltage level V_(Tx2) of the power output through the power transmitting coil C_(Tx2) or may control the voltage level of the driving power V_(DC2) to adjust the voltage level V_(Tx2) of the power output through the power transmitting coil C_(Tx2), thereby controlling the power transferred to the second power receiving coil C_(Rx2).

Since information on the position, charging state, operating state, charging power, and the like, of the battery B is continuously needed for the power charging of the charger A, the information may be transferred through bidirectional communications between the communications unit 111 c of the charger A and the communications unit Com of the battery B. In addition, information on the positions, power transmitting states, power switching operations, charging power, and the like, of the power transmitting coils C_(Tx1) and C_(Tx2) of the charger A may be transferred to the battery B through the communications unit Com of the battery B.

FIG. 12 is a circuit diagram schematically illustrating an example of controlling power transmitted from a charger to a plurality of batteries according to an exemplary embodiment in the present disclosure.

Referring to FIG. 12, the charger A according to an exemplary embodiment in the present disclosure may transmit power to a plurality of batteries B1 and B2 in a non-contact manner.

Each of the batteries B1 and B2 may include at least one power receiving coil. For example, each battery may include six power receiving coils C_(Rx1), C_(Rx2), C_(Rx3), C_(Rx4), C_(Rx5), and C_(Rx6).

Similar to the embodiment illustrated in FIG. 11, the power transmitting units Tx1 and Tx2 of the charger A may include power transmitting coils C_(Tx1) and C_(Tx2) and switching units 111 b 1 and 111 b 2. The switching units 111 b 1 and 111 b 2 may transfer power to the power transmitting coils C_(Tx1) and C_(Tx2), respectively, in order to calculate the coupling coefficients between the power transmitting side and the power receiving side.

The switches Q11, Q21, Q12, and Q22 of the switching units 111 b 1 and 111 b 2 may switch driving power V_(DC1) and V_(DC2) depending on switching control signals SQ11, SQ21, SQ12, and SQ22 from the switching control unit 111 a to transmit the power to the power receiving side through the corresponding power transmitting coils C_(Tx1) and C_(Tx2) in the non-contact manner.

The switching control unit 111 a may control the power switching of the switching units 111 b 1 and 111 b 2 depending on the information of the battery B transferred by the communications unit 111 c. For example, the switching control unit 111 a may control respective switching duties or the on-off dead times of the switches Q11, Q21, Q12, and Q22 to adjust voltage levels V_(Tx1) and V_(Tx2) of the power output through the power transmitting coils C_(Tx1) and C_(Tx2), or may control voltage levels of the driving power V_(DC1) and V_(DC2) to adjust the voltage levels V_(Tx1) and V_(Tx2) of the power output through the power transmitting coils C_(Tx1) and C_(Tx2), or may control switching frequencies to adjust frequencies f_(Tx1) and f_(Tx2) at which the power is transmitted by the power transmitting coils C_(Tx1) and C_(Tx2).

The above-mentioned adjusting or controlling operation may be performed on the basis of the coupling coefficients between the power transmitting side and the power receiving side.

As an example, in a case in which a coupling coefficient between the first power transmitting coil C_(Tx1) and a first power receiving coil C_(Rx1) of a first battery B1 is low, the first power transmitting unit Tx1 may control respective switching frequencies of the switches Q11 and Q21 of the switching unit 111 b 1 to control the frequency f_(Tx1) at which the power is transmitted by the power transmitting coil C_(Tx1), in order to effectively control the power transferred to the first power receiving coil C_(Rx1) of the first battery B1.

As another example, in a case in which a coupling coefficient between the second power transmitting coil C_(Tx2) and a second power receiving coil C_(Rx2) of a second battery B2 is high, the second power transmitting unit Tx2 may control respective switching duties or on-off dead times of the switches Q12 and Q22 of the switching unit 111 b 2 to adjust the voltage level V_(Tx2) of the power output through the power transmitting coil C_(Tx2) or may control the voltage level of the driving power V_(DC2) to adjust the voltage level V_(Tx2) of the power output through the power transmitting coil C_(Tx2), thereby controlling the power transferred to the second power receiving coil C_(Rx2) of the second battery B2.

In addition, each of the first and second power transmitting units Tx1 and Tx2 may be controlled to transmit the power to the first battery B1 at a first frequency, for example, a frequency of 100 to 300 kHz according to the wireless power consortium (WPC) standard and to transmit the power to the second battery B2 at a second frequency that is relatively high, for example, a frequency of 6.78 MHz according to the alliance for wireless power (A4WP) standard.

In addition, the power may be transmitted to the first power receiving coil C_(Rx1) of the first battery B1 at the frequency of the WPC standard and may be transmitted to the second power receiving coil C_(Rx2) of the first battery B1 at the frequency of the A4WP standard.

Since information on the positions, charging states, operating states, charging power, and the like, of the batteries B1 and B2 is continuously needed for the power charging of the charger A, the information may be transferred through bidirectional communications between the charger A and the batteries B1 and B2. In addition, information on the positions, power transmitting states, power switching operations, charging power, and the like, of the power transmitting coils C_(Tx1) and C_(Tx2) of the charger A may be transferred to the batteries B1 and B2.

FIGS. 13A through 13D are views illustrating an example of a switching control of an active rectifier in a battery according to an exemplary embodiment in the present disclosure.

Referring to FIG. 13A, the battery B according to an exemplary embodiment in the present disclosure may receive power transmitted in a non-contact manner through the power receiving coil CRx. Here, a voltage and a current of the received power may have a phase difference, whereby power efficiency may deteriorate.

The battery B according to the exemplary embodiment may include an active rectifying unit La.

For example, the rectifying unit La may include four switches S1, S2, S3, and S4 connected to each other in a full bridge structure.

A control unit Lc may provide gate signals SS1, SS2, SS3, and SS4 to control a switching operation of the rectifying unit La in a pulse width modulation (PWM) scheme.

For example, as illustrated in FIG. 13B, the control unit Lc may compare a carrier signal having a frequency higher than a transmission frequency of the power transmitted in the non-contact manner with an output current of the power receiving coil CRx to provide gate signals of the first and second switches S1 and S2. In this case, each of the third and fourth switches S3 and S4 may be turned on during a half period of the power transmitted in the non-contact manner, as illustrated in FIG. 13C. For example, the fourth switch S4 may be turned on during a positive half period of the power transmitted in the non-contact manner, and the third switch S3 may be turned on during a negative half period of the power transmitted in the non-contact manner.

Referring to FIG. 13D, a reference signal required for controlling the output current of the power receiving coil CRx may be controlled using a hysteresis band which means an interval between an upper limit and a lower limit of the output current of the power receiving coil CRx.

When a width of the above-mentioned hysteresis band is decreased, ripples of the output current of the power receiving coil CRx may be decreased such that the output current of the power receiving coil CRx may be precisely controlled, while the switching frequencies of the switches S1, S2, S3, and S4 of the rectifying unit La may be increased such that power loss may be increased.

As set forth above, according to exemplary embodiments in the present disclosure, amounts of power transmitted at the time of charging the battery cells with the power may be adjusted for each of the battery cells depending on coupling coefficients between the power transmitting coils and the power receiving coils to maintain a balance in power levels between the battery cells or rapidly charge the battery cells with the maximum allowable current.

While exemplary embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations could be made without departing from the scope of the present invention as defined by the appended claims. 

What is claimed is:
 1. A non-contact type power receiver comprising: a plurality of power receiving coils receiving power in a non-contact manner; a plurality of rectifying units switching to rectify the power received from the plurality of power receiving coils; and a control unit controlling the switching by the plurality of rectifying units to control respective levels of the power rectified by the plurality of rectifying units, wherein each of the plurality of rectifying units has a full bridge structure including first and second switches forming one leg and third and fourth switches forming the other leg connected to the one leg in parallel, and wherein the control unit compares a carrier signal having a frequency higher than a transmission frequency of the power transmitted to the plurality of power receiving coils with a current reference signal of the received power, and controls the switching of the first and second switches using a pulse width modulation (PWM) scheme, depending on a comparison result.
 2. The non-contact type power receiver of claim 1, wherein the control unit turns the fourth switch on in a positive half period of power from a corresponding power receiving coil and turns the third switch on in a negative half period of the power from the corresponding power receiving coil.
 3. The non-contact type power receiver of claim 1, wherein the current reference signal is set depending on a hysteresis band, which indicates an interval between an upper limit and a lower limit of a current level of the received power.
 4. A non-contact type power receiver comprising: a plurality of power receiving coils receiving power in a non-contact manner; a plurality of rectifying units switching to rectify the power received from the plurality of power receiving coils; and a control unit controlling the switching by the plurality of rectifying units, depending on coupling coefficients between each of the plurality of power receiving coils and a plurality of power transmitting coils which transmit the power to the plurality of power receiving coils, to control respective levels of the power rectified by the plurality of rectifying units, wherein each of the plurality of rectifying units has a full bridge structure including first and second switches forming one leg and third and fourth switches forming the other leg connected to the one leg in parallel, and wherein the control unit compares a carrier signal having a frequency higher than a transmission frequency of the power transmitted to the plurality of power receiving coils with a current reference signal of the received power, and controls the switching of the first and second switches using a pulse width modulation (PWM) scheme, depending on a comparison result.
 5. The non-contact type power receiver of claim 4, wherein the control unit turns the fourth switch on in a positive half period of power from a corresponding power receiving coil and turns the third switch on in a negative half period of the power from the corresponding power receiving coil.
 6. The non-contact type power receiver of claim 4, wherein the current reference signal is set depending on a hysteresis band, which indicates an interval between an upper limit and a lower limit of a current level of the received power.
 7. A non-contact type battery comprising: a plurality of power receiving coils receiving power in a non-contact manner; a plurality of rectifying units switching to rectify the power received from the plurality of power receiving coils; a plurality of regulators regulating the power rectified by the plurality of rectifying units into charging power; a plurality of battery cells charged with the charging power from the plurality of regulators; and a control unit controlling the switching by the plurality of rectifying units to control respective levels of the power charged in the plurality of battery cells, wherein each of the plurality of rectifying units has a full bridge structure including first and second switches forming one leg and third and fourth switches forming the other leg connected to the one leg in parallel, and wherein the control unit compares a carrier signal having a frequency higher than a transmission frequency of the power transmitted to the plurality of power receiving coils with a current reference signal of the received power, and controls the switching of the first and second switches using a pulse width modulation (PWM) scheme, depending on a comparison result.
 8. The non-contact type battery of claim 7, wherein the control unit turns the fourth switch on in a positive half period of power from a corresponding power receiving coil and turns the third switch on in a negative half period of the power from the corresponding power receiving coil.
 9. The non-contact type battery of claim 7, wherein the current reference signal is set depending on a hysteresis band, which indicates an interval between an upper limit and a lower limit of a current level of the received power.
 10. The non-contact type battery of claim 7, wherein the control unit controls the switching by the plurality of rectifying units, depending on coupling coefficients between each of the plurality of power receiving coils and a plurality of power transmitting coils which transmit the power to the plurality of power receiving coils. 